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Date:         Wed, 26 Dec 2007 18:52:07 -0800
Reply-To:     Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject:      Re: 1.9 low power problem
Comments: To: Evan Mac Donald <macdonald1987@SBCGLOBAL.NET>
In-Reply-To:  <555480.96710.qm@web81714.mail.mud.yahoo.com>
Content-Type: text/plain; charset="us-ascii"

The splash shields are nice to have on there, but they don't really do that much. Not likely that they alone are a major factor. I can't quite agree with the "02 is signal is ignored if the ecu doesn't like it. The ecu will try to deal with a dead 02, it just can't do anything with that signal, I don't think it knows to quite ignore it. Perhaps you meant it can't do much with a dead or shorted 02 signal. But I don't think it's smart enough to go 'ooops, this doesn't' make sense, I better ignore it' ...........I think it would just stay in open loop - just like it would if the 02 was disconnect. For one, the 02 has to be warm enough to produce a signal and then the system is in 'closed loop' . If he 02 is dead, then it would run in open loop and not run as nicely, burn more fuel etc. It can run with the 02 disconnected. Checking that the 02 is shorted by water is a very good thing to look into.

You should always read what the 02 is doing with a meter. You tap into the signal wire and you'd like to see swinging voltage, like .4 to .8 volts, something like that. If it's say .5 volts continuous, it's dead - this is well warmed up. 02 is out of the picture during wide open throttle I believe. I would sure be spraying electrical things with WD-40 if running in the wet makes it run poorly. I like the checking for water shorting the 02 signal though. Man, I would love to have a whole bunch of 'switch-in standard default signals' ............one for 02, one for ecu temp sender, etc. Then if you think a sensor is faulty, as a test you just switch in the 'standard mid-range default value' straight to the ecu, and if that removes the symptom, you know exactly where to look. It's really fun when you can play with the system this way. It's not even that complicated. A few inputs here and there, and the ecu ( and ignition system if you have a 1.9 ) controls spark, when spark occurs, and how long the injectors are open. It's quite odd that the ecu can't tell if the Cat is doing anything. In more modern systems, OBD-II, there's an 02 downstream of the cat and the ecu can tell if that's working. Some systems even shut off fuel to individual misfiring cylinders. All fun ! Scott www.turbovans.com

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Evan Mac Donald Sent: Wednesday, December 26, 2007 12:23 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: 1.9 low power problem

I am so sorry - i should have said "...and APPEAR after driving for a while..." This is because the O@ sensor is ignored by the ECU until its signal "makes sense" to the ECU, but it may not be the right signal for conditions...

Brendan Slevin <brendan@BELLATAZZA.COM> wrote: These symptoms did start after driving through tons of rainy slush and snow. But, they don't go away after awhile, they might not get worse, but they are certainly persistant and not going away. Also, should there be some kind of splash guards on the sides?s

Brendan Slevin

Roastmaster

BELLATAZZA

tel 541 593.9750

www.bellatazza.com

I have measured out my life with coffee spoons. -T.S. Eliot

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of Evan Mac Donald Sent: Wednesday, December 26, 2007 11:56 AM To: vanagon@GERRY.VANAGON.COM Subject: Re: 1.9 low power problem

IF these symptoms arose AFTER the van got wet, AND go away AFTER running awhile, the O2 sensor is a suspect. Unplug the sensor wire, and try the same driving course, to try to duplicate the problem...

Brendan Slevin wrote: Well, Totoro has been running great since the rebuild but now (last three days) has developed a hesitation. It drives fine in town but when I try to get on it to get up to highway speed in 3rd or 4th it bogs way down and if I don't lift seems as though it would die all they way. If I lift my foot and slow a bit and down shift it seems fine again until the instant I try to speed up again. Happening right around 4000 rpm on the tach. Plugged cat maybe? I took some connections apart and cleaned them with elec. Cleaner in a spray can. Even unplugged the ecu and plugged it back in. I did this all this morning before starting the van. When I started it and warmed it up I took it for a test drive. Was fine for about three miles and then started it again. We've had a ton of snow and slush last week so I think something got wet. Maybe the water causing the problem was frozen this morning (25 degrees F) and didn't cause a problem until thawing out. Also, am I supposed to have and splash guards around the engine? Seems to be hole to mount some on both side in the wheel wells.

Brendan I have measured out my life with coffee spoons. -T.S. Eliot


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